Add function-no-unknown

[gnuletik]

Which issue, if any, is this issue related to?

Closes #5853

Is there anything in the PR that needs further explanation?

"No, it's self-explanatory."

[gnuletik]

There's an issue on Windows builds when loading css-functions-list:

ENOENT: no such file or directory, open '/D:/a/stylelint/stylelint/node_modules/css-functions-list/cjs/index.json'

Does someone use Windows and have an idea to fix it?

[ybiquitous]

@gnuletik How about using URL as below?

fs.readFileSync(new URL("file://" + listPath))

[gnuletik]

@gnuletik How about using URL as below?

fs.readFileSync(new URL("file://" + listPath))

I just made the change. I need approval to run the CI.

[ybiquitous]

@gnuletik Thanks, almost good! 👍🏼

[ybiquitous]

Thanks, LGTM 👍🏼

[jeddy3]

Thanks for the pull request.

I've requested some changes. Let's also add an accept test for TRANSFORM and an reject one for UNKNOWN.

[gnuletik]

Thanks @jeddy3 !
I applied your changes, added some test for the if (!isStandardSyntaxFunction) { ... } branch and rebased.

[jeddy3]

Thanks for making the changes.

I've requested a couple more.

Let's also add an:

• accept test for TRANSFORM
• an reject one for UNKNOWN

So that we test that the rule is case insensitive.

[jeddy3]

Suggested change

	This rule ignores double-dashed custom functions, e.g. --custom-function().
	This rule ignores double-dashed custom functions, e.g. `--custom-function()`.

Minor nit.

[jeddy3]

Let's move this SCSS into its own testRule that uses the postcss-scss syntax as we strive to keep standard and non-standard syntax separate, like so.

[jeddy3]

Thanks for making the changes.

One last suggestion and I think we're ready to merge.

[jeddy3]

Suggested change

	ruleName,
	config: true,
	skipBasicChecks: true,
	ruleName,
	config: true,
	customSyntax: "postcss-scss",
	skipBasicChecks: true,

Let's specify the SCSS syntax (even though the default parser can parse the construct) to be explicit.

[jeddy3]

Thanks for making the changes. LGTM.

[jeddy3]

Changelog entry:

• Added: function-no-unknown rule (#5865).

[torhovland]

This is now starting to complain when I have

@use 'sass:math';

.service-detail-header-logo__active-icon {
  top: math.div(-$pulse-size, 4);
  ...

Unexpected unknown function "math.div"  function-no-unknown

Although the workaround is to downgrade stylelint-config-standard, not stylelint itself. Hmm...

[ybiquitous]

@torhovland It is an issue of stylelint-scss: ⬇️

stylelint-scss/stylelint-scss#581

[ybiquitous]

As a workaround, you can disable the rule like this:

{
  "overrides": [
    {
      "files": ["*.scss", "**/*.scss"],
      "rules": {
        "function-no-unknown": null
      }
    }
  ]
}

[ybiquitous]

@torhovland #5901 will be released with the next version 14.5.0 (#5902). You can re-enable the rule until stylelint-scss/stylelint-scss#581 is implemented like this:

{
  "overrides": [
    {
      "files": ["*.scss", "**/*.scss"],
      "rules": {
        "function-no-unknown": [true, { "ignoreFunctions": ["math.div"] }]
      }
    }
  ]
}

[kristerkari]

The SCSS version is now also available:
https://github.com/stylelint-scss/stylelint-scss/releases/tag/v4.2.0